1. Field of the Invention
The present invention relates to novel alkaline protease API-21 and the preparation method thereof. More specifically, it relates to alkaline protease API-21 derived from a bacterium and having an enzymatic activity even at a relatively low temperature (e.g., room temperature to about 40.degree. C.) under an alkaline condition and also relates to a method for preparing the same from the cultivation of novel species of NKS-21 belonging to genus Bacillus.
2. Description of the Prior Art
Alkaline protease is widely used in the fields of, for example, a leather industry, a food industry, a fiber or textile industry, or a medicine or pharmaceutical industry; the reason is said to be that alkaline protease is rather stable against heat as compared with neutral protease. Furthermore, market demand for enzmes as a detergent additive has recently increased. Enzymes practically used as a detergent additive are alkaline proteases derived from bacteria belonging to genus Bacillus, which exhibit a maximum activity at a pH of about 9 to about 10. Most of the above-mentioned enzymes exhibit a maximum activity at a relatively high temperature, especially around 60.degree. C., but are inactive or less active at a relatively low temperature, especially around a room temperature. This means that the characteristics of enzymes are not fully utilized in such a country as in Japan, where clothes are generally washed at room temperature. Furthermore, the development of enzymes having a retained enzymatic activity even at a relatively low temperature is needed due to the recent increased usage of chemical fiber clothes having a relatively low heat stability and also due to the recent energy-saving movement.